A hard disk drive apparatus (hereinafter also referred to as an HDD (Hard-Disk Drive)) is widely used for an information processing apparatus, e.g., a personal computer, as an electronic device (recording and reproducing apparatus) in which data and programs are written and from which recorded data and the like are read. Not only an HDD built in a main body of the information processing apparatus, but also a portable type or detachable type HDD attachable/detachable to/from the main body of the information processing apparatus is known. The HDD is independently carried or stored apart from the main body of the information processing apparatus.
The portable HDD typically includes a metal housing, and a single HDD unit or a plurality of HDD units housed in the housing. In addition, in order to protect the HDD unit(s) from an external force such as a shock, it is known that block-shaped shock-damping components are attached to four corners of an HDD unit, or the respective plurality of HDD units are fixed to the housing via the shock-damping material, for example (see Patent Literatures 1 to 3).